Receiving interference and noise power fluctuations reports from a user equipment

ABSTRACT

A base station is configured to receive channel state information (CSI) from a user equipment (UE). The base station transmits configuration information including one or more interference measurement resources (IMRs) allocated for measurement by the UE, receives a reference CSI report from the UE, receives a new CSI report including interference and noise power fluctuation feedback from the UE and selects a modulation and coding scheme (MCS) for the UE based on at least the interference and noise power fluctuation feedback and the reference CSI report.

BACKGROUND

In 5G new radio (NR) wireless communications, the 5G NR network mayassign one or more frequency sub-bands to a user equipment (UE) toexchange information with the network. These sub-bands are allocated tothe UE based on measured channel conditions that the UE reports to anext generation-NodeB (gNB) of the network. In addition, an optimalmodulation and coding scheme (MCS) is selected by the network based onthe measured channel conditions. A mean signal-to-noise and interferenceratio (SINR) and a SINR standard deviation may be used by the UE tomodel the SINR and reported to the network to help the gNB select theoptimal MCS. Alternatively, the SINR can be modelled using a gammadistribution for improved power control.

SUMMARY

Some exemplary embodiments are related to a base station having atransceiver configured to communicate with a user equipment (UE) and aprocessor communicatively coupled to the transceiver and configured toperform operations. The operations include transmitting configurationinformation including one or more interference measurement resources(IMRs) allocated for measurement by the UE, receiving a reference CSIreport from the UE, receiving a new CSI report including interferenceand noise power fluctuation feedback from the UE and selecting amodulation and coding scheme (MCS) for the UE based on at least theinterference and noise power fluctuation feedback and the reference CSIreport.

Other exemplary embodiments relate to one or more processors that areconfigured to perform operations. The operations include transmittingconfiguration information including one or more interference measurementresources (IMRs) allocated for measurement by a user equipment (UE),receiving a reference CSI report from the UE, receiving a new CSI reportincluding interference and noise power fluctuation feedback from the UEand selecting a modulation and coding scheme (MCS) for the UE based onat least the interference and noise power fluctuation feedback and thereference CSI report.

Still further exemplary embodiments relate to a method that includestransmitting configuration information including one or moreinterference measurement resources (IMRs) allocated for measurement by auser equipment (UE), receiving a reference CSI report from the UE,receiving a new CSI report including interference and noise powerfluctuation feedback from the UE and selecting a modulation and codingscheme (MCS) for the UE based on at least the interference and noisepower fluctuation feedback and the reference CSI report.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary network arrangement according to variousexemplary embodiments.

FIG. 2 shows an exemplary UE according to various exemplary embodiments.

FIG. 3 shows an exemplary base station configured to establish aconnection with a user equipment according to various exemplaryembodiments.

FIG. 4 shows a method of reporting interference fluctuation according tovarious exemplary embodiments.

FIG. 5 shows exemplary resource blocks allocated by a g-NodeB to a UEfor interference measurements according to various exemplaryembodiments.

DETAILED DESCRIPTION

The exemplary embodiments may be further understood with reference tothe following description and the related appended drawings, whereinlike elements are provided with the same reference numerals. Theexemplary embodiments describe a device, system and method for a userequipment (UE) connected to a 5G new radio (NR) network to determinecell interference fluctuation and provide feedback regarding suchinterference fluctuation to a next generation-NodeB (gNB) of thenetwork.

The exemplary embodiments are described with regard to a network thatincludes 5G new radio NR radio access technology (RAT). However, theexemplary embodiments may be implemented in other types of networksusing the principles described herein.

The exemplary embodiments are also described with regard to a UE.However, the use of a UE is merely for illustrative purposes. Theexemplary embodiments may be utilized with any electronic component thatmay establish a connection with a network and is configured with thehardware, software, and/or firmware to exchange information and datawith the network. Therefore, the UE as described herein is used torepresent any electronic component.

Deployment of ultra-reliable and low latency communications (URLLC) isexpected to be in the frequency range 1 (FR1) of NR because the channelstate does not vary as easily as frequency range 2 (FR2). As such, achange in the signal-to-noise and interference ratio (SINR) is moreoften caused by fluctuations in interference than by channel variations.Such interference may be caused by, for example, other cellinterference, multiuser (MU) interference, etc. 5G NR has an increasedflexibility in physical downlink control channel (PDCCH)monitoring/mini-slot scheduling that may cause an increase ininterference fluctuation. However, tasking a UE with sending frequentCSI reports to the gNB is extremely burdensome on the UE (e.g.,increased monitoring, increased power consumption, etc.).

According to some exemplary embodiments, a new Channel State Information(CSI) report quantity may be defined in so that the UE can send a CSIreport including only interference and noise measurements instead of aconventional CSI report including other channel measurements as well.Such a report would advantageously be less burdensome on the UE andwould provide the gNB with more useful information in determining amodulation and coding scheme (MCS) to be used.

FIG. 1 shows an exemplary network arrangement 100 according to variousexemplary embodiments. The exemplary network arrangement 100 includes aUE 110. It should be noted that any number of UEs may be used in thenetwork arrangement 100. Those skilled in the art will understand thatthe UE 110 may alternatively be any type of electronic component that isconfigured to communicate via a network, e.g., mobile phones, tabletcomputers, desktop computers, smartphones, phablets, embedded devices,wearables, Internet of Things (IoT) devices, etc. It should also beunderstood that an actual network arrangement may include any number ofUEs being used by any number of users. Thus, the example of a single UE110 is merely provided for illustrative purposes.

The UE 110 may be configured to communicate with one or more networks.In the example of the network configuration 100, the networks with whichthe UE 110 may wirelessly communicate are a 5G New Radio (NR) radioaccess network (5G NR-RAN) 120, an LTE radio access network (LTE-RAN)122 and a wireless local access network (WLAN) 124. However, it shouldbe understood that the UE 110 may also communicate with other types ofnetworks and the UE 110 may also communicate with networks over a wiredconnection. Therefore, the UE 110 may include a 5G NR chipset tocommunicate with the 5G NR-RAN 120, an LTE chipset to communicate withthe LTE-RAN 122 and an ISM chipset to communicate with the WLAN 124.

The 5G NR-RAN 120 and the LTE-RAN 122 may be portions of cellularnetworks that may be deployed by cellular providers (e.g., Verizon,AT&T, T-Mobile, etc.). These networks 120, 122 may include, for example,cells or base stations (Node Bs, eNodeBs, HeNBs, eNBS, gNBs, gNodeBs,macrocells, microcells, small cells, femtocells, etc.) that areconfigured to send and receive traffic from UE that are equipped withthe appropriate cellular chip set. The WLAN 124 may include any type ofwireless local area network (WiFi, Hot Spot, IEEE 802.11x networks,etc.).

The UE 110 may connect to the 5G NR-RAN 120 via the gNB 120A and/or thegNB 120B. During operation, the UE 110 may be within range of aplurality of gNBs. Thus, either simultaneously or alternatively, the UE110 may connect to the 5G NR-RAN 120 via the gNBs 120A and 120B.Further, the UE 110 may communicate with the eNB 122 A of the LTE-RAN122 to transmit and receive control information used for downlink and/oruplink synchronization with respect to the 5G NR-RAN 120 connection.

Those skilled in the art will understand that any association proceduremay be performed for the UE 110 to connect to the 5G NR-RAN 120. Forexample, as discussed above, the 5G NR-RAN 120 may be associated with aparticular cellular provider where the UE 110 and/or the user thereofhas a contract and credential information (e.g., stored on a SIM card).Upon detecting the presence of the 5G NR-RAN 120, the UE 110 maytransmit the corresponding credential information to associate with the5G NR-RAN 120. More specifically, the UE 110 may associate with aspecific base station (e.g., the gNB 120A of the 5G NR-RAN 120).

In addition to the networks 120, 122 and 124 the network arrangement 100also includes a cellular core network 130, the Internet 140, an IPMultimedia Subsystem (IMS) 150, and a network services backbone 160. Thecellular core network 130 may be considered to be the interconnected setof components that manages the operation and traffic of the cellularnetwork, e.g. the 5GC for NR. The cellular core network 130 also managesthe traffic that flows between the cellular network and the Internet140.

The IMS 150 may be generally described as an architecture for deliveringmultimedia services to the UE 110 using the IP protocol. The IMS 150 maycommunicate with the cellular core network 130 and the Internet 140 toprovide the multimedia services to the UE 110. The network servicesbackbone 160 is in communication either directly or indirectly with theInternet 140 and the cellular core network 130. The network servicesbackbone 160 may be generally described as a set of components (e.g.,servers, network storage arrangements, etc.) that implement a suite ofservices that may be used to extend the functionalities of the UE 110 incommunication with the various networks.

FIG. 2 shows an exemplary UE 110 according to various exemplaryembodiments. The UE 110 will be described with regard to the networkarrangement 100 of FIG. 1. The UE 110 may represent any electronicdevice and may include a processor 205, a memory arrangement 210, adisplay device 215, an input/output (I/O) device 220, a transceiver 225and other components 230. The other components 230 may include, forexample, an audio input device, an audio output device, a battery thatprovides a limited power supply, a data acquisition device, ports toelectrically connect the UE 110 to other electronic devices, one or moreantenna panels, etc. For example, the UE 110 may be coupled to anindustrial device via one or more ports.

The processor 205 may be configured to execute a plurality of engines ofthe UE 110. For example, the engines may include a CSI management engine235. The CSI management engine 235 may perform various operationsrelated to measuring interference on allocated interference measurementblocks (IMR) and providing interference fluctuation feedback to thenetwork (e.g., via the gNB 120A or 120B).

The above referenced engine being an application (e.g., a program)executed by the processor 205 is only exemplary. The functionalityassociated with the engine may also be represented as a separateincorporated component of the UE 110 or may be a modular componentcoupled to the UE 110, e.g., an integrated circuit with or withoutfirmware. For example, the integrated circuit may include inputcircuitry to receive signals and processing circuitry to process thesignals and other information. The engines may also be embodied as oneapplication or separate applications. In addition, in some UE, thefunctionality described for the processor 205 is split among two or moreprocessors such as a baseband processor and an applications processor.The exemplary embodiments may be implemented in any of these or otherconfigurations of a UE.

The memory arrangement 210 may be a hardware component configured tostore data related to operations performed by the UE 110. The displaydevice 215 may be a hardware component configured to show data to a userwhile the I/O device 220 may be a hardware component that enables theuser to enter inputs. The display device 215 and the I/O device 220 maybe separate components or integrated together such as a touchscreen. Thetransceiver 225 may be a hardware component configured to establish aconnection with the 5G NR-RAN 120, the LTE-RAN 122, the WLAN 124, etc.Accordingly, the transceiver 225 may operate on a variety of differentfrequencies or channels (e.g., set of consecutive frequencies).

FIG. 3 shows an exemplary network cell, in this case gNB 120A, accordingto various exemplary embodiments. The gNB 120A may represent any accessnode of the 5G NR network through which the UEs 110 may establish aconnection. The gNB 120A illustrated in FIG. 3 may also represent thegNB 120B.

The gNB 120A may include a processor 305, a memory arrangement 310, aninput/output (I/O) device 320, a transceiver 325, and other components330. The other components 330 may include, for example, a power supply,a data acquisition device, ports to electrically connect the gNB 120A toother electronic devices, etc.

The processor 305 may be configured to execute a plurality of engines ofthe gNB 120A. For example, the engines may include a modulation andcoding scheme (MCS) management engine 335 for performing operationsincluding determining an MCS for a UE based on interference fluctuationfeedback received from the UE. Examples of this process will bedescribed in greater detail below.

The above noted engine being an application (e.g., a program) executedby the processor 305 is only exemplary. The functionality associatedwith the engines may also be represented as a separate incorporatedcomponent of the gNB 120A or may be a modular component coupled to thegNB 120A, e.g., an integrated circuit with or without firmware. Forexample, the integrated circuit may include input circuitry to receivesignals and processing circuitry to process the signals and otherinformation. In addition, in some gNBs, the functionality described forthe processor 305 is split among a plurality of processors (e.g., abaseband processor, an applications processor, etc.). The exemplaryaspects may be implemented in any of these or other configurations of agNB.

The memory 310 may be a hardware component configured to store datarelated to operations performed by the UEs 110, 112. The I/O device 320may be a hardware component or ports that enable a user to interact withthe gNB 120A. The transceiver 325 may be a hardware component configuredto exchange data with the UE 110 and any other UE in the system 100. Thetransceiver 325 may operate on a variety of different frequencies orchannels (e.g., set of consecutive frequencies). Therefore, thetransceiver 325 may include one or more components (e.g., radios) toenable the data exchange with the various networks and UEs.

FIG. 4 shows a method 400 of reporting interference fluctuationaccording to various exemplary embodiments. The method 400 of FIG. 4includes providing the network (e.g., gNB) with a new type of CSI reportthat includes only interference and noise measurements be lessburdensome on the UE but still provide the network with information fordetermining a modulation and coding scheme (MCS) to be used. As will bedescribed below, a reference report may be generated and linked to thenew CSI report to provide normalized values for the reporting of theinterference and noise in the new CSI report. Thus, throughout thisdescription, the term “new CSI report” will refer to the CSI report thatincludes only interference and noise measurements and “reference CSIreport” will refer to a report that provides the network with normalizedvalues for the new CSI report. The new CSI report may also includemultiple SINRs or SINR statistics. The SINR is based on a ratio of areference signal (the desired signal) versus the interference-plus noisemeasurement. Thus, the desired signal may be used to normalize the newCSI report. In the example of FIG. 4, it may be considered that the UE110 is camped on the gNB 120A and will be providing the reference CSIreport and the new CSI report to the gNB 120A.

At 405, the UE receives configuration information from the gNB 120Aidentifying resource elements (REs) as interference measurementresources (IMRs) for which the UE 110 is to determine an interferencefluctuation. In some embodiments, the IMRs are within the same slot. Insome embodiments, the IMRs may alternatively or additionally be acrossdifferent slots. Examples of IMRs will be provided below with referenceto FIG. 5.

At 410, the UE 110 determines a noise power (PNoise) associated with azero power (ZP) interference measurement resource (IMR) to generate aconventional CSI report. As those skilled in the art will understand,zero-power means that the resource element is used for a non-zero power(NZP) CSI reference signal (CSI RS) from a different component, e.g.,the gNB 120B. Thus, at 410, the UE 110 measures the CSI RS from gNB 120Bfor the purposes of normalizing the interference and noise values to beincluded in the new CSI report in subsequent operations. At 415, the UE110 sends a reference CSI report to the gNB 120A (e.g., a channelquality indicator (CQI), a rank indicator (RI), a precoding matrixindicator (PMI), etc.). In some embodiments, if the new CSI reportincludes multiple SINRs and/or SINR statistics, at 410, the UE 110determines a desired signal power associated with the channelmeasurement resource (CMR) to generate a conventional CSI report.

The reference CSI report may be sent to the gNB 120A based on a numberof factors. For example, the reference CSI reports may be sent by the UE110 based on a schedule, on a periodic basis, based on an event (e.g., arequest from the gNB 120A, a mobility threshold of the UE 110, etc.),etc. Thus, the reference CSI report may correspond to one or more newCSI reports, e.g., the normalized values in the reference CSI report maybe used for one or more new CSI reports. Thus, the operations 410 and415 are related to generating and reporting the reference CSI report. Aswill be described in greater detail below, the operations 420 and 425are related to generating and reporting the new CSI report. Theoperations 420 and 425 (new CSI report) may be performed multiple timesfor a single instance of performing the operations 410 and 415(reference CSI report). In some embodiments, the conventional report andthe new CSI report may be sent together.

At 420, the UE 110 performs interference measurements on the IMRsallocated to the UE 110 by the gNB 120A (at 405). It should beunderstood that the IMRs used for the interference measurements mayinclude none/part of/all of the IMRs configured for the conventional CSIreport. At 425, the UE 110 provides interference fluctuation feedback tothe gNB 120A so that the gNB 120A may determine the MCS for the UE 110given the interference fluctuation. The interference feedback will bedescribed in greater detail below. As described above, this feedback maybe a new CSI report defined as “Interference+Noise Only” or “multipleSINRs and/or SINRs statistics.” The reference CSI report (from 415) maybe functionally linked to the new CSI report so that the reference CSIreport can serve as a baseline (benchmark).

For purposes of reporting the values in the new CSI report, the type offeedback may depend on the number of IMRs that are to be measured andreported. The following examples use the number of four (4) IMRs as anexemplary threshold for reporting. However, it should be understood thatthe threshold may be set at any value. In some exemplary embodiments, ifthe number of IMRs is less than or equal to four (4) IMRs, the UE 110reports a normalized interference and noise power (measured interferenceand noise power with respect to P_(Noise)) to the gNB 120A for each IMR.In some embodiments, if the number of IMRs is greater than four (4)IMRs, the noise/interference may alternatively be modelled using, forexample, a gamma distribution so that the UE 110 is not overburdenedwith reporting a large number of interference and noise power values. Insuch a scenario, the UE 110 may include the parameters for the modellingin the feedback provided to the gNB 120A. In the case of a gammadistribution, these parameters are γ and m, where γ is averageinterference and noise power and m is a shape factor. The probabilitydensity function is defined as

${P_{\overset{\_}{\gamma},m}(\gamma)} = {\frac{m^{m}\gamma^{m - 1}}{{\overset{\_}{\gamma}}^{m}{\Gamma(m)}}e^{\frac{{- m}\gamma}{\overset{\_}{\gamma}}}}$

where Γ(m) is the gamma function. If m is large, then there isessentially little variation in the observed interference and noisepower. If, however, m is small, then there are possibly substantialfluctuations in the interference and noise power. To determine theparameters γ and m, the UE 110 may use the following functions

$\hat{\overset{\_}{\gamma}} = {\sum\limits_{k = 1}^{K}\gamma_{k}}$$\hat{m} = \frac{1}{2\left( {{\log\hat{\overset{\_}{\gamma}}} - \frac{\sum_{k = 1}^{K}{\log\gamma_{k}}}{K}} \right)}$

where γ_(k) is the measured interference and noise power in a given IMRk, with 1≤k≤K. In some embodiments, {circumflex over (γ)} is normalizedusing the CSI report based on the IMRs of the reference signal. In someembodiments, uniform quantization in the log domain with saturation maybe used. In some embodiments, {circumflex over (m)} is quantized with anon-uniform range such as, for example, <1, [1, 10), [10 20]), [20,200), [200, +∞). The intervals for both {circumflex over (γ)} and{circumflex over (m)} may either be specified in the 3GPP standards orconfigured via RRC.

The tail distribution of the statistical model may be of differingimportance to the gNB scheduling depending on whether it is on the lowertail or the higher tail. For example, when forming the statisticalmodel, fitting the higher tail for interference plus noise (or the lowertail for SINR) may be prioritized by the UE. In some exemplaryembodiments, the UE processing to prioritize fitting on the higher tailfor interference plus noise or the lower tail for SINR may be defined bythe relevant standards (e.g., 3GPP standards), may be signaled to the UEby the network or may be preprogrammed into the UE.

FIG. 5 shows resource blocks of an exemplary reference signal allocatedby the gNB 120A to the UE 110 for interference measurements according tovarious exemplary embodiments. These resource blocks are merelyillustrative examples of the IMRs allocated for the UE 110 by the gNB120A for interference and noise power measurements. As noted above, theIMRs 502 a-c in slot 1 or 504 a-c in slot 2 may within the same slot or,alternatively, the IMRS 502 a-c and 504 a-c may be across differentslots (slot 1 and slot 2). The more IMRs allocated to the UE 110, themore measurements the UE 110 can take, which advantageously helps thegNB 120A select the MCS.

Those skilled in the art will understand that the above-describedexemplary embodiments may be implemented in any suitable software orhardware configuration or combination thereof. An exemplary hardwareplatform for implementing the exemplary embodiments may include, forexample, an Intel x 86 based platform with compatible operating system,a Windows OS, a Mac platform and MAC OS, a mobile device having anoperating system such as iOS, Android, etc. In a further example, theexemplary embodiments of the above described method may be embodied as aprogram containing lines of code stored on a non-transitory computerreadable storage medium that, when compiled, may be executed on aprocessor or microprocessor.

Although this application described various aspects each havingdifferent features in various combinations, those skilled in the artwill understand that any of the features of one aspect may be combinedwith the features of the other aspects in any manner not specificallydisclaimed or which is not functionally or logically inconsistent withthe operation of the device or the stated functions of the disclosedaspects.

It is well understood that the use of personally identifiableinformation should follow privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining the privacy of users. In particular,personally identifiable information data should be managed and handledso as to minimize risks of unintentional or unauthorized access or use,and the nature of authorized use should be clearly indicated to users.

It will be apparent to those skilled in the art that variousmodifications may be made in the present disclosure, without departingfrom the spirit or the scope of the disclosure. Thus, it is intendedthat the present disclosure cover modifications and variations of thisdisclosure provided they come within the scope of the appended claimsand their equivalent.

What is claimed:
 1. A base station, comprising: a transceiver configuredto communicate with a user equipment (UE); and a processorcommunicatively coupled to the transceiver and configured to performoperations comprising: transmitting configuration information includingone or more interference measurement resources (IMRs) allocated formeasurement by the UE; receiving a reference CSI report from the UE;receiving a new CSI report including interference and noise powerfluctuation feedback from the UE; and selecting a modulation and codingscheme (MCS) for the UE based on at least the interference and noisepower fluctuation feedback and the reference CSI report.
 2. The basestation of claim 1, wherein the interference and noise power fluctuationfeedback comprises a measured interference and noise power for each IMRand wherein the operations further comprise: normalizing the measuredinterference and noise power for each IMR based on the noise power forthe corresponding IMR in the reference CSI report.
 3. The base stationof claim 1, wherein the interference and noise power fluctuationfeedback comprises parameters to model interference and noise powerfluctuation.
 4. The base station of claim 3, wherein a gammadistribution is used to model the interference and noise powerfluctuation, and wherein the parameters include the average interferenceand noise power (γ) and a shape factor (m).
 5. The base station of claim4, wherein the operations further comprise: normalizing γ based on atleast the noise power of the IMR in the reference CSI report; andquantizing m with a non-uniform range.
 6. The base station of claim 6,wherein the non-uniform range comprises ranges including one of lessthan 1, from 1 to 10, from 10 to 20, from 20 to 200 and from 200 toinfinity.
 7. The base station of claim 1, wherein the one or more IMRsare one of in a same slot or are in different slots.
 8. The base stationof claim 1, wherein the base station is a next generation node B (gNB)of a New Radio (NR) network.
 9. The base station of claim 6, wherein theone or more IMRs are in the Frequency Range 1 (FR1) of the NR network.10. One or more processors configured to perform operations comprising:transmitting configuration information including one or moreinterference measurement resources (IMRs) allocated for measurement by auser equipment (UE); receiving a reference CSI report from the UE;receiving a new CSI report including interference and noise powerfluctuation feedback from the UE; and selecting a modulation and codingscheme (MCS) for the UE based on at least the interference and noisepower fluctuation feedback and the reference CSI report.
 11. The one ormore processors of claim 10, wherein the interference and noise powerfluctuation feedback comprises a measured interference and noise powerfor each IMR and wherein the operations further comprise: normalizingthe measured interference and noise power for each IMR based on thenoise power for the corresponding IMR of the reference CSI report. 12.The one or more processors of claim 10, wherein the interference andnoise power fluctuation feedback comprises parameters to modelinterference and noise power fluctuation.
 13. The one or more processorsof claim 12, wherein a gamma distribution is used to model theinterference and noise power fluctuation, and wherein the parametersinclude the average interference and noise power (γ) and a shape factor(m).
 14. The one or more processors of claim 13, wherein the operationsfurther comprise: normalizing γ based on at least the noise power of theIMR in the reference CSI report; and quantizing m with a non-uniformrange.
 15. The one or more processors of claim 14, wherein thenon-uniform range comprises ranges including one of less than 1, from 1to 10, from 10 to 20, from 20 to 200 and from 200 to infinity.
 16. Amethod, comprising: transmitting configuration information including oneor more interference measurement resources (IMRs) allocated formeasurement by a user equipment (UE); receiving a reference CSI reportfrom the UE; receiving a new CSI report including interference and noisepower fluctuation feedback from the UE; and selecting a modulation andcoding scheme (MCS) for the UE based on at least the interference andnoise power fluctuation feedback and the reference CSI report.
 17. Themethod of claim 16, wherein the interference and noise power fluctuationfeedback comprises a measured interference and noise power for each IMR,the method further comprising: normalizing the measured interference andnoise power for each IMR based on the noise power for the correspondingIMR of the reference CSI report.
 18. The method of claim 16, wherein theinterference and noise power fluctuation feedback comprises parametersto model interference and noise power fluctuation.
 19. The method ofclaim 18, wherein a gamma distribution is used to model the interferenceand noise power fluctuation, and wherein the parameters include theaverage interference and noise power (γ) and a shape factor (m).
 20. Themethod of claim 19, further comprising: normalizing γ based on at leastthe noise power of the IMR in the reference CSI report; and quantizing mwith a non-uniform range.